﻿using Microsoft.DirectX;
using Microsoft.DirectX.DirectSound;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;

namespace altest
{
  class SoundRecorder
  {

    #region 成员数据  
    private Capture mCapDev = null;              // 音频捕捉设备  
    private CaptureBuffer mRecBuffer = null;     // 缓冲区对象  
    private WaveFormat mWavFormat;               // 录音的格式  

    private int mNextCaptureOffset = 0;         // 该次录音缓冲区的起始点  
    private int mSampleCount = 0;               // 录制的样本数目  

    private Notify mNotify = null;               // 消息通知对象  
    public const int cNotifyNum = 16;           // 通知的个数  
    private int mNotifySize = 0;                // 每次通知大小  
    private int mBufferSize = 0;                // 缓冲队列大小  
    private Thread mNotifyThread = null;                 // 处理缓冲区消息的线程  
    private AutoResetEvent mNotificationEvent = null;    // 通知事件  

    private string mFileName = string.Empty;     // 文件保存路径  
    private FileStream mWaveFile = null;         // 文件流  
    private BinaryWriter mWriter = null;         // 写文件  
    #endregion
    #region 对外操作函数  
    /// <summary>  
    /// 构造函数,设定录音设备,设定录音格式.  
    /// <summary>  
    public SoundRecorder()
    {
      //初始化音频捕捉设备  
      InitCaptureDevice();
      //设定录音格式  
      mWavFormat = CreateWaveFormat();
    }

    /// <summary>  
    /// 创建录音格式,此处使用16bit,16KHz,Mono的录音格式  
    /// <summary>  
    private WaveFormat CreateWaveFormat()
    {
      WaveFormat format = new WaveFormat();
      format.FormatTag = WaveFormatTag.Pcm;   //PCM  
      format.SamplesPerSecond = 16000;        //采样率：16KHz  
      format.BitsPerSample = 16;              //采样位数：16Bit  
      format.Channels = 1;                    //声道：Mono  
      format.BlockAlign = (short)(format.Channels * (format.BitsPerSample / 8));  //单位采样点的字节数   
      format.AverageBytesPerSecond = format.BlockAlign * format.SamplesPerSecond;
      return format;
      //按照以上采样规格，可知采样1秒钟的字节数为 16000*2=32000B 约为31K  
    }

    /// <summary>  
    /// 设定录音结束后保存的文件,包括路径  
    /// </summary>  
    /// <param name="filename">保存wav文件的路径名</param>  
    public void SetFileName(string filename)
    {
      mFileName = filename;
    }

    /// <summary>  
    /// 开始录音  
    /// </summary>  
    public void RecStart()
    {
      // 创建录音文件  
      CreateSoundFile();
      // 创建一个录音缓冲区，并开始录音  
      CreateCaptureBuffer();
      // 建立通知消息,当缓冲区满的时候处理方法  
      InitNotifications();
      mRecBuffer.Start(true);
    }


    /// <summary>  
    /// 停止录音  
    /// </summary>  
    public void RecStop()
    {
      mRecBuffer.Stop();      // 调用缓冲区的停止方法，停止采集声音  
      if (null != mNotificationEvent)
        mNotificationEvent.Set();       //关闭通知  
      mNotifyThread.Abort();  //结束线程  
      RecordCapturedData();   // 将缓冲区最后一部分数据写入到文件中  

      // 写WAV文件尾  
      mWriter.Seek(4, SeekOrigin.Begin);
      mWriter.Write((int)(mSampleCount + 36));   // 写文件长度  
      mWriter.Seek(40, SeekOrigin.Begin);
      mWriter.Write(mSampleCount);                // 写数据长度  

      mWriter.Close();
      mWaveFile.Close();
      mWriter = null;
      mWaveFile = null;
    }
    #endregion

    #region 对内操作函数  
    /// <summary>  
    /// 初始化录音设备,此处使用主录音设备.  
    /// </summary>  
    /// <returns>调用成功返回true,否则返回false</returns>  
    private bool InitCaptureDevice()
    {
      // 获取默认音频捕捉设备  
      var devices = new CaptureDevicesCollection();  // 枚举音频捕捉设备  
      Guid deviceGuid = Guid.Empty;

      if (devices.Count > 0)
        deviceGuid = devices[0].DriverGuid;
      else
      {
        //MessageBox.Show("系统中没有音频捕捉设备");
        return false;
      }

      // 用指定的捕捉设备创建Capture对象  
      try
      {
        mCapDev = new Capture(deviceGuid);
      }
      catch (DirectXException e)
      {
        //MessageBox.Show(e.ToString());
        return false;
      }
      return true;
    }

    /// <summary>  
    /// 创建录音使用的缓冲区  
    /// </summary>  
    private void CreateCaptureBuffer()
    {
      // 缓冲区的描述对象  
      var bufferdescription = new CaptureBufferDescription();
      if (null != mNotify)
      {
        mNotify.Dispose();
        mNotify = null;
      }
      if (null != mRecBuffer)
      {
        mRecBuffer.Dispose();
        mRecBuffer = null;
      }
      // 设定通知的大小,默认为1s钟  
      mNotifySize = (1024 > mWavFormat.AverageBytesPerSecond / 8) ? 1024 : (mWavFormat.AverageBytesPerSecond / 8);
      mNotifySize -= mNotifySize % mWavFormat.BlockAlign;
      // 设定缓冲区大小  
      mBufferSize = mNotifySize * cNotifyNum;
      // 创建缓冲区描述  
      bufferdescription.BufferBytes = mBufferSize;
      bufferdescription.Format = mWavFormat;           // 录音格式  
                                                       // 创建缓冲区  
      mRecBuffer = new CaptureBuffer(bufferdescription, mCapDev);
      mNextCaptureOffset = 0;
    }

    /// <summary>  
    /// 初始化通知事件,将原缓冲区分成16个缓冲队列,在每个缓冲队列的结束点设定通知点.  
    /// </summary>  
    /// <returns>是否成功</returns>  
    private bool InitNotifications()
    {
      if (null == mRecBuffer)
      {
        //MessageBox.Show("未创建录音缓冲区");
        return false;
      }
      // 创建一个通知事件,当缓冲队列满了就激发该事件.  
      mNotificationEvent = new AutoResetEvent(false);
      // 创建一个线程管理缓冲区事件  
      if (null == mNotifyThread)
      {
        mNotifyThread = new Thread(new ThreadStart(WaitThread));
        mNotifyThread.Start();
      }
      // 设定通知的位置  
      BufferPositionNotify[] PositionNotify = new BufferPositionNotify[cNotifyNum + 1];
      for (int i = 0; i < cNotifyNum; i++)
      {
        PositionNotify[i].Offset = (mNotifySize * i) + mNotifySize - 1;
        PositionNotify[i].EventNotifyHandle = mNotificationEvent.SafeWaitHandle.DangerousGetHandle();
      }
      mNotify = new Notify(mRecBuffer);
      mNotify.SetNotificationPositions(PositionNotify, cNotifyNum);
      return true;
    }

    /// <summary>  
    /// 接收缓冲区满消息的处理线程  
    /// </summary>  
    private void WaitThread()
    {
      while (true)
      {
        // 等待缓冲区的通知消息  
        mNotificationEvent.WaitOne(Timeout.Infinite, true);
        // 录制数据  
        RecordCapturedData();
      }
    }

    /// <summary>  
    /// 将录制的数据写入wav文件  
    /// </summary>  
    private void RecordCapturedData()
    {
      byte[] CaptureData = null;
      int ReadPos = 0, CapturePos = 0, LockSize = 0;
      mRecBuffer.GetCurrentPosition(out CapturePos, out ReadPos);
      LockSize = ReadPos - mNextCaptureOffset;
      if (LockSize < 0)       // 因为是循环的使用缓冲区，所以有一种情况下为负：当文以载读指针回到第一个通知点，而Ibuffeoffset还在最后一个通知处  
        LockSize += mBufferSize;
      LockSize -= (LockSize % mNotifySize);   // 对齐缓冲区边界,实际上由于开始设定完整,这个操作是多余的.  
      if (0 == LockSize)
        return;

      // 读取缓冲区内的数据  
      CaptureData = (byte[])mRecBuffer.Read(mNextCaptureOffset, typeof(byte), LockFlag.None, LockSize);
      // 写入Wav文件  
      mWriter.Write(CaptureData, 0, CaptureData.Length);
      // 更新已经录制的数据长度.  
      mSampleCount += CaptureData.Length;
      // 移动录制数据的起始点,通知消息只负责指示产生消息的位置,并不记录上次录制的位置  
      mNextCaptureOffset += CaptureData.Length;
      mNextCaptureOffset %= mBufferSize; // Circular buffer  
    }

    /// <summary>  
    /// 创建保存的波形文件,并写入必要的文件头.  
    /// </summary>  
    private void CreateSoundFile()
    {
      // Open up the wave file for writing.  
      mWaveFile = new FileStream(mFileName, FileMode.Create);
      mWriter = new BinaryWriter(mWaveFile);
      //Here is where the file will be created. A  
      //wave file is a RIFF file, which has chunks  
      //of data that describe what the file contains.  
      //A wave RIFF file is put together like this:  
      //The 12 byte RIFF chunk is constructed like this:  
      //Bytes 0 - 3 :  'R' 'I' 'F' 'F'  
      //Bytes 4 - 7 :  Length of file, minus the first 8 bytes of the RIFF description.  
      //                  (4 bytes for "WAVE" + 24 bytes for format chunk length +  
      //                  8 bytes for data chunk description + actual sample data size.)  
      // Bytes 8 - 11: 'W' 'A' 'V' 'E'  
      // The 24 byte FORMAT chunk is constructed like this:  
      // Bytes 0 - 3 : 'f' 'm' 't' ' '  
      // Bytes 4 - 7 : The format chunk length. This is always 16.  
      // Bytes 8 - 9 : File padding. Always 1.  
      // Bytes 10- 11: Number of channels. Either 1 for mono,  or 2 for stereo.  
      // Bytes 12- 15: Sample rate.  
      // Bytes 16- 19: Number of bytes per second.  
      // Bytes 20- 21: Bytes per sample. 1 for 8 bit mono, 2 for 8 bit stereo or  
      //                 16 bit mono, 4 for 16 bit stereo.  
      // Bytes 22- 23: Number of bits per sample.  
      // The DATA chunk is constructed like this:  
      // Bytes 0 - 3 : 'd' 'a' 't' 'a'  
      // Bytes 4 - 7 : Length of data, in bytes.  
      // Bytes 8 -: Actual sample data.  
      // Set up file with RIFF chunk info.  
      char[] ChunkRiff = { 'R', 'I', 'F', 'F' };
      char[] ChunkType = { 'W', 'A', 'V', 'E' };
      char[] ChunkFmt = { 'f', 'm', 't', ' ' };
      char[] ChunkData = { 'd', 'a', 't', 'a' };

      short shPad = 1;                // File padding  
      int nFormatChunkLength = 0x10;  // Format chunk length.  
      int nLength = 0;                // File length, minus first 8 bytes of RIFF description. This will be filled in later.  
      short shBytesPerSample = 0;     // Bytes per sample.  

      // 一个样本点的字节数目  
      if (8 == mWavFormat.BitsPerSample && 1 == mWavFormat.Channels)
        shBytesPerSample = 1;
      else if ((8 == mWavFormat.BitsPerSample && 2 == mWavFormat.Channels) || (16 == mWavFormat.BitsPerSample && 1 == mWavFormat.Channels))
        shBytesPerSample = 2;
      else if (16 == mWavFormat.BitsPerSample && 2 == mWavFormat.Channels)
        shBytesPerSample = 4;

      // RIFF 块  
      mWriter.Write(ChunkRiff);
      mWriter.Write(nLength);
      mWriter.Write(ChunkType);

      // WAVE块  
      mWriter.Write(ChunkFmt);
      mWriter.Write(nFormatChunkLength);
      mWriter.Write(shPad);
      mWriter.Write(mWavFormat.Channels);
      mWriter.Write(mWavFormat.SamplesPerSecond);
      mWriter.Write(mWavFormat.AverageBytesPerSecond);
      mWriter.Write(shBytesPerSample);
      mWriter.Write(mWavFormat.BitsPerSample);

      // 数据块  
      mWriter.Write(ChunkData);
      mWriter.Write((int)0);   // The sample length will be written in later.  
    }
    #endregion
    // */
  }
}